Varicella (Chickenpox)

Boy in bed with fever Boy in bed with fever

Chickenpox is a very common childhood infection. It is caused by a virus called varicella-zoster (said like VAH-ri-sell-ah ZAW-ster).

The infection is usually mild in children. But newborn babies and adults can become very sick if they get chickenpox.

Normally, our immune system protects us from infections. Chickenpox is very dangerous to people with immune system problems like leukemia, or anyone taking drugs that weaken the immune system. This includes steroids and drugs given to help organ transplant patients.

What is shingles?

Shingles looks like chickenpox and is caused by the same virus. However, it usually appears on only one part of the body. Shingles happens when the virus flares up again after hiding in the body for some time. Only people who have already had chickenpox can get shingles. You cannot get shingles from someone who has chickenpox.

Symptoms of chickenpox

Chickenpox usually begins with a fever. A day or two later, your child will get a rash that can be very itchy. The rash starts as red spots.

These red spots soon turn into fluid-filled blisters. Some people have only a few blisters. Other people can have as many as 500. These blisters dry up and form scabs in four or five days.

Chickenpox spreads through contact or small droplets in the air

Chickenpox spreads easily. It jumps from person to person in two ways:

  • Through direct contact with the virus, when someone touches the blisters.
  • Through saliva droplets in the air, when someone with chickenpox sneezes, coughs, or even talks.

The virus spreads most easily one or two days before the rash appears. A child with chickenpox can give the infection to other people until the blisters have dried up. Contact your school or daycare to find out when your child can return.

If one of your children has chickenpox, it will probably spread to other members of the household who are not already immune. If someone else catches the infection, it will usually appear two to three weeks after the first family member got it.

A pregnant woman with chickenpox can pass it on to her unborn baby. Mothers with chickenpox can also give it to their newborn babies after birth. Chickenpox in pregnant women and newborns is often more serious.

Treating chickenpox at home

If your child gets chickenpox, do not give acetylsalicylic acid (ASA or Aspirin) or any products that contain ASA. Taking ASA increases the risk of getting Reye's syndrome. This severe illness can damage a child's liver and brain.

To control your child's fever, use acetaminophen (said like ah-SEE-tah-MIN-oh-fen.) Your pharmacist can help you choose an anti-fever medicine with acetaminophen​.

The chickenpox rash is very itchy. Take good care of the skin and make sure your child does not scratch it. A child who scratches a lot may get infections caused by bacteria that get into the skin. You can do the following things to prevent this:

  • Cut your child's fingernails short.
  • Dress your child in light-weight clothing.
  • Give your child luke-warm baths to help reduce the itch.
  • If your child feels well enough, let her play and be active. This can take her mind off the itch.
  • Your doctor may tell you the name of a cream to help reduce the itch.

These are some warning signs that bacteria has infected your child's skin through a blister:

  • A new fever
  • Infected skin is hot to the touch
  • Pus from an infected blister
  • Swelling and pain in the infected area

A bacterial skin infection should be treated by a doctor.

A free vaccine can prevent chickenpox

A vaccine is medicine that causes the body's immune system to make protective proteins. These proteins are called antibodies. They can protect a person from infection for a long time.

All healthy children should get the chickenpox vaccine when they are one year old. This is the advice of the Canadian Paediatric Society and the National Advisory Committee on Immunization. In Ontario, this vaccine is free. The vaccine also works and is safe for toddlers, children, teenagers, and adults.

If your child has not had the vaccine and she touches or plays with another child who has chickenpox, your child can be protected if she gets the vaccine right away.

For more information about when vaccines should be given, see "Immunization Schedule."

If your child has a weakened immune system and you think she might have chickenpox, call your doctor

If your child has an immune system disorder, or is taking drugs that weaken the immune system, call your doctor right away. Your child may be treated with one of the following medicines:

  • medicine called VZIG (varicella-zoster immune globulin). VZIG has a large number of antibodies to help prevent chickenpox. This medicine is given by injection (a needle).
  • an anti-viral medicine that makes the infection less serious
  • other treatment recommended by your doctor

People do not usually get chickenpox twice

In most cases, when you get chickenpox once you will not get it again. This is called life-long immunity. But in rare cases, a person might get it again.

Chickenpox can cause problems for pregnant women

Pregnant women can get severe chickenpox.

If you are thinking of getting pregnant and have not had chickenpox, ask your doctor about getting the vaccine.

If you are pregnant, you should answer these questions about chickenpox:

Have you already had chickenpox?

Yes __  No __

Have you had the chickenpox vaccine?

Yes __  No __

Have you lived in the same house as someone infected with chickenpox or shingles?

Yes __  No __

If you said No to all three questions, stay away from people with chickenpox. At some times during your pregnancy, chickenpox could hurt your unborn baby. Call your doctor right away if you are exposed to chickenpox.

If you said Yes to any of the questions, you are probably already protected against chickenpox. Many adult women are already protected against chickenpox by antibodies in their blood, even if they do not remember getting chickenpox as a child.

Children with chickenpox get different care in hospitals

If your child is in hospital, she might get different treatment so she does not give chickenpox to other people. Special care rules called isolation precautions mean your child might get a private room, or stay near other children who also have chickenpox.

If your child goes to the hospital and you think she might have chickenpox, tell a nurse

If your child has already had chickenpox or the chickenpox vaccine, your child cannot get the infection. But if your child has never had chickenpox or the vaccine, and has had close contact with someone with chickenpox within the last three weeks, your child may be infected.

Close contact means playing, touching, or sitting close.

Let the doctor, nurse or registration person know right away that your child was exposed to chickenpox. They may need to take special care with your child to make sure the infection does not spread to other people. The virus spreads most easily before the rash appears. It is important to make sure chickenpox does not spread in hospitals, because some children there may not be able to fight the infection. ​​

Laurie Streitenberger, RN, BSc, CIC

Karen Breen-Reid, RN, MN

Anne Matlow, MD, FRCPC